


Exchanges

by Daebak



Category: Sherlock (TV)
Genre: (of sorts), A Scandal In Belgravia, AU, Assassin Mary, BAMF Mary, BAMF Sherlock, Backstory, Friendship, Gen, Minor Violence, Missing Scene, What really happened in Karachi?
Language: English
Status: Completed
Published: 2016-07-08
Updated: 2016-07-08
Packaged: 2018-07-22 06:17:57
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,898
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7423366
Author URL: https://archiveofourown.org/users/Daebak/pseuds/Daebak
Summary: <blockquote class="userstuff">
              <p>When Sherlock arrives in Karachi to infiltrate a terrorist cell for the one woman who has ever fascinated him, he is approached by a blonde assassin looking for an escape. She proposes a partnership.</p>
            </blockquote>





	Exchanges

**Exchanges**

Two weeks. It had gone a mere _two weeks_ since Sherlock had bid her goodbye and left her to run, run, run, however far she could. And run she had before Moriarty caught up with her – not the man himself, no, but the web he'd stretched tightly across England and most of South Asia (not to mention the tendrils of his network across the globe) was sticky with his influence, and she had become quickly entangled in it.

Despite the betrayal Sherlock felt at the time – and it was strange, to feel so strongly _betrayed_ by a woman who had used him from the very beginning – he had kept tabs on her, unbeknownst to his brother who would undoubtedly meddle.

As far as John knew, he was off on a case in Aberdeen to investigate the death of a tourist who had planned a trip from London to Scotland on a wet winter's day and ended up drowning to death in a puddle of water not five centimetres deep.

"Barely a three," Sherlock said, putting on his coat with an air of deep inconvenience.

John, who had been treading on eggshells around Sherlock for whatever reason since the case with The Woman, lowered his paper and stared at him. "You're taking a _seven-hour trip by train_ both ways for a case that's barely a three?"

"You know my methods, John. If I fail to follow the man's _exact_ trail, I'll be no better than those incompetent idiots down at the Yard." Sherlock grabbed a small travel case and headed for the door. "I'll be back by Tuesday."

"Sherlock," John called, and Sherlock stopped short. When he turned around, face impassive, the doctor's eyes were studying him, as if he could deduce the detective as he so often did John. "Look," he said seriously, "if you're going somewhere dangerous…"

_Like to Karachi to infiltrate a terrorist cell, perhaps?_

" _Do_ stop wasting your time worrying, John." Sherlock turned back to the door and said over his shoulder as he headed down the stairs: "And remember to pick up some milk. I've used it all in the experiment with the fingers." He ignored whatever John shouted behind him and slammed the door shut.

How tedious, to be misled by so simple a distraction.

But as Sherlock stepped out into the chill, dry air of Pakistan, he half wished that John _were_ at his side, lifting his face up to a familiar yellow sun from a previous life. He brushed away the irrelevant thought and pulled his cap down lower on his head.

Preoccupied with deducing which cab driver was trustworthy enough to take him directly to his motel without detours, he failed to notice the pair of clear blue eyes that lingered on him for just a bit too long from behind a magazine.

* * *

The knock on his door was unexpected. His senses were immediately alert, a dozen dozen wires firing in his head.

His eyes went to the crack beneath the door, but the hallway was too dark to make out a shadow. He listened for a shifting of weight by the person standing outside, but it was futile; whoever was outside was unmoving, as still and silent as stone.

The knock came again: sharp, unhesitating. A firm hit with the metacarpophalangeal joints of the index and second fingers. This time, Sherlock could tell the knocker was between 5'3" and 5'5", judging by the height of their hand against the door and the sharpness of the hits. Likely a woman, then.

" _Mhujhey tang na karoh*_ ," he snarled. He thrust the niqab that he had just pulled out of his bag onto the cot and crept silently to the door. He had no _time_ for distractions. And despite his efforts, he felt tense and impatient; in the dead of the night in a foreign country, heading into dangers unknown, he felt an excitement, yes – but deep in his bones there was a growing anxiety that he abhorred to acknowledge.

He heard a shuffling of feet – was the woman leaving? No. To his deep annoyance, she was moving closer to the door. God help him, he had no time for this. He opened his mouth to speak when to his surprise, he heard a low – but amused? menacing? (unclear, further data needed) – voice.

English. A woman in her early thirties.

"Are you going to let me in or shall I break the door down?"

Further data needed.

He jerked the door open (ignoring the faint admonishment in the back of his head that sounded suspiciously like John's) and the woman slipped inside as quickly as a breeze, closing the door behind her with hardly a sound.

She grinned up at him like an old friend, presumably to put him at ease.

But at once he glimpsed in her eyes what others would have easily missed. What others – so boring, so vapid – failed to see in John Watson, the hint of something the doctor often denied he had, if not to Sherlock then to himself: an underlying energy, a heartbeat that drummed constantly. _Danger,_ he heard. _Danger, danger._ She hid it not as convincingly as the former soldier, as if she were immersed in it rather than riding on its edge.

"Sherlock Holmes, yes?" she asked, ignoring his scrutiny and clearly already knowing the answer. She was still smiling benignly, her back to the door. The woman was dressed in a dark blue salwar karmeez, a beige dupatta draped over her head and across her shoulders. She wore the costume as if it were her natural look – and yet, it was just that: a costume. A curl of blond hair stuck out from under her right ear. Her eyes were bright and steady as she looked at him.

His hands itched for a weapon to grip out of instinct; but while the whiff of _danger_ lingered about the woman, something about the way she held herself was evidence enough for Sherlock that she was not there to harm him.

Sherlock was fascinated. "You're no client," he said.

"No," she said, and then she tilted her head to the side. "Not exactly."

Interesting.

His mind fired off a string of deductions: _baker, romantic, size 11 – no, 12, linguist, sleeps on her side, clever, arrived in Pakistan two days prior, confident, quick on her feet. Dangerous._

So caught up was he in his initial deductions – because something about this seemingly ordinary woman was not _quite_ adding up, but he could not figure it out (think, think, _think_ ) – that she took him off guard when she said abruptly, "I want to propose a partnership of sorts." Her fingers tapped at her side in sequence like an incomplete piano scale, four staccato notes over and over again. Nervous habit, but from the look of her fingertips, one that was newly ingrained.

Her fingertips. Calloused. They reminded him of…

"I don't need a partnership," he said after a pause. "I already have a partner."

The tapping ceased, her hand clenched, and the smile faded from her face. But instead of looking aggressive, she looked apprehensive; either she had expected a different answer, or she was second guessing herself.

No, not herself. She was doubting if she had come to the right person.

After one quiet moment where Sherlock, slightly affronted, guessed she was listening for people outside of the door, she reached up and drew her scarf down, revealing a head of curly blond hair pinned up in a tight bun.

"I looked you up," she said, voice strong, "and I think I can help you on your mission."

"Help me how?" Sherlock narrowed his eyes at her. He was still missing one piece of the puzzle. It was as if she was standing behind a sheet of water: at once tantalizingly visible but angled in ways that tricked and muddled the eye. She was _very_ well trained, if fraying at the edges – and suddenly everything clicked. _Obvious._ "You don't seem very threatening – save for the handgun on your left hip and the sheathed dagger on your forearm." The woman's eyes widened. "You're uncomfortable right now, in this room; but you're uncomfortable because the salwar karmeez doesn't allow for direct access to your gun, not because of me in particular. Strange. I also wonder," he continued smoothly, "what business does an American assassin – East Coast, I assume – have in Karachi, and why does she sport an English accent that is still rather unpolished?"

She lifted her hands from her side in a placating gesture – as if he _hadn't_ already known that she wasn't going to use her weapons on him – and shook her head slowly in disbelief and awe.

"So it's true," she murmured, and to his shock, she looked… pleased. He frowned uncertainly at her, but her eyes lit up; and smiling once more, she declared, "God, you're _brilliant_. This is perfect."

Sherlock blinked. "What?"

"You're not safe here."

"Here –?"

"In Karachi," she interrupted, still looking at him intently with large blue eyes. "Whatever you're heading into, you're underestimating it. And that," she said, nodding toward the black niqab on the cot, "and _that_ ," she added, with a pointed look at the full-length mirror behind which he had hidden a machete, "don't exactly paint a pretty picture. And whatever you say you are, detective, you're no killer."

She tapped her side once more, where the handgun was hidden. "I can help you," she repeated. "Be your partner for this one mission, since your regular one seems to be absent." Her lips were quirked in a smile. She was wholly confident in whatever assistance she was offering Sherlock. However, she was not offering it freely. She had come to _him_ for a reason.

So he asked skeptically, "In exchange for _what_?"

She shook her head fiercely. "We haven't time for this. You plan on heading back to England in approximately six hours, which means you must complete your mission in the next four. Tell me."

Sherlock had questions – and that was rare enough – but the woman was right. Time was against him. And besides, she had ignited his curiosity. An assassin, coming to him with an offer of aid?

"How do I know I can trust you?"

"You _don't_ know," she said truthfully. "And I won't say you should go with 'what your heart is telling you'—" She bent her fingers up and down, which Sherlock remembered John saying were 'air quotes'. Ridiculous. "—but you can do your – your thing. Deduce. Do you think I'm a threat? To you?"

There she stood, with her gun and her dagger and the clothes that weren't hers. The face and posture he couldn't easily decipher. And yet – "Not to me," he murmured.

She nodded, satisfied. "Good. Now brief me on your mission."

"You keep saying 'mission'. Why 'mission'?"

"Mission. Task. Quest. Case. Whatever you want to call it."

"None of those. I'm here on a…" He hesitated. What was he to call this? "A personal errand."

"An errand," she said drily. "One doesn't come to Karachi with a 28-inch machete on an _errand_. A trip to the shops for milk is an errand."

"For an… acquaintance. A woman who would sell out England if it would save herself. The man she worked for – he caught her in his web." He knew he would make little sense to the common outsider, but she did not seem to be bothered; in fact, she looked more considering than confused. But still, he did not expect her next question.

"Are you here to kill her?" she asked bluntly, face betraying no emotion.

He balked at the very thought. "No, I'm here to prevent that from happening."

"And the machete?"

"I'm her executioner."

A pause.

A smile. "Good. Where's the execution?"

Sherlock removed his phone from his pocket and – after swiping away two unread texts from John, likely written in caps, probably about the milk and the fingers – handed it to the woman, the screen opened to a text from an unknown number. When the text had arrived two days ago with the familiar alert noise that made Mrs Hudson go rushing from the room (which made him notice she had been there in the first place) it had taken him a quick online search and four minutes to crack it.

It took her less than three with no internet connection, which both impressed and irked him.

_Qaidabad, edge of the Malir River, 0400,_ the decoded message read.

"Great, I know exactly where that is." The eagerness in her voice was unmistakable.

"You've not been there."

"No," she replied casually. "But I did my research. Qaidabad's a prime spot for the Pakistani mafia to gather and – er – negotiate, and near the Malir there's a nice, large, _empty_ lot that would be perfect for beheadings. I'm sure the terrorists will be happy to borrow it for a while."

Sherlock decided that he rather approved of this woman. Astonishingly unassuming to the average human eye – though John, so foolishly driven by his hormones, would likely deem her 'attractive' on whatever scale he used to measure such values – but… interesting. Unpredictable. He didn't even know her name, and she hadn't offered it, though it seemed to be the first piece of information ordinary people expected to exchange with each other. This woman, she wasn't even making an effort to appear ordinary. At least, not in front of him.

"What's your plan?" he asked her. She was covering her hair back up with the dupatta, a new energy in her eyes. Two fingers tapped her side to check for the handgun and her wrist flexed imperceptibly to feel for the presence of a dagger on her forearm; the movements were so instinctual that Sherlock doubted she even noticed them.

With the voice of an officer, she fired off a sequence of events she had already formulated in her mind: "You incapacitate them. Blade to gut or knees. Your friend goes free. Let her run off. I was never involved."

"Except."

" _Except_ I'll be somewhere in the area neutralizing the people you've incapacitated." Her tone was steady and aloof, like a surgeon going over a routine procedure with his nurses. He did not ask her how, exactly, she would be 'neutralizing' the terrorists; he suspected that she would find his question superfluous. "All good with the plan?"

He nodded. "I need to get dressed."

"Great," she said. "Let me go fetch my sniper rifle. See you in two."

Staring at her disappearing back, he felt, for the first time in many years, that he was the one encumbering the professional.

* * *

A moan. _Goodbye Mr Holmes._

It went down better than he had expected, when all was said and done.

She told him to stay behind her – "You'll get blood on your niqab prematurely" – as she took care of the guards with silent flicks of the knife, covering their mouths as they cried out and catching them as they fell to muffle the sounds. For a small woman, she was surprisingly strong. She nodded to him once, sharply, then made her way to a building on the far side of where the execution was taking place.

Despite his growing tension, he couldn't deny the thrill of entering the dark, open lot; speaking low, his mind swiftly navigating the unfamiliar nuances of Urdu and earning the confidence of the hooded men; and finally, as The Woman's eyes closed in resignation, swinging his machete in a full circle instead of downwards. The men, caught by surprise, were easy enough to subdue.

Irene Adler did not thank him. As the last man went down with a blow to the knees, she caught his chin between two slim fingers and pulled him toward her.

Sherlock stilled as the cold barrel of a gun was pressed against the bottom of his neck.

"I just saved your life," he protested indignantly. He could hear muffled gunshots ringing out from behind him as his one-time partner finished off each of the terrorists with calm precision.

The Woman glanced at a man as he jerked on the ground from a bullet to his skull, then back to Sherlock. "I need your clothes," she whispered, her lips brushing the tip of his ear, the gun pressing ever more firmly at his neck. He groaned.

Minutes later, a woman in black fled from the scene, another approached it warily – then promptly burst out in laughter.

"You're starkers!"

"Shut up."

She lent him her scarf on the dark, dark way back to the motel.

* * *

"Did she know you would come?" she asked as he stepped back into the room, fully dressed once more. She had already cleaned her knife and disassembled her gun, and was sitting on his cot, elbows on knees, watching him. Only the slight dark shadows under her eyes spoke of the long and bloody night.

She had known exactly what to do with the bodies, how to leave no trace of them – and Sherlock and herself – behind.

"The Woman…" Sherlock started, gazing at a space on the wall where a picture had once hung. In his mind, he saw The Woman, felt her pulse, heard her voice, her plea. "She knows how to play people like chess pieces. She sent me a puzzle, _knowing_ that I would try and solve it. _Knowing_ that I would come here. Yes, I expect she was certain I would come, though I don't know if she expected that I _wouldn't_ follow through with the swing. But I let her go, twice now, so she got the better of me again."

He smiled at the thought – not bitterly, not sorrowfully, not joyfully, but simply acknowledging the enigma that was The Woman – and for a while, the room was silent. Each of them in their own head.

The clock ticked on, and soon both their bags were packed, the woman having brought her meager belongings – one suitcase only – to his larger room.

"Now tell me, what's my part of the deal?" Sherlock said, raising his eyebrows at the woman who now stood before him.

Her eyes flicked away and down to the rough carpet, and for only the second time that night, he saw in her a hint of uncertainty.

"I need erasure," she said quietly, "and…" She hesitated. "Rebirth."

Sherlock nodded slowly. "Witness protection?"

"Of sorts."

"Erasure of your entire life. The creation of another."

"Yes."

"And what, exactly, do you hope to gain from this? You seem perfectly capable of running away and hiding in some unknown corner of the world where no one would ever find you. You don't need my help."

She shook her head. "No, Mr. Holmes. You see – erasing someone entirely is easy. _Creating_ someone entirely is another story, and that's where I need your help. I don't want to hide; I want to _live_. Just… not as who as I am now."

She was overestimating him, Sherlock thought. Despite his work as a consulting detective, he did not have the ability to erase someone off the surface of the earth – nor to create a convincing life from scratch – so he told her so.

The woman gave a shrug. "You might not be able to, but your brother can."

Sherlock tried not to show the shock on his face, but the woman was perceptive; she smiled slightly. How did she know about Mycroft? And know not only of Mycroft, but of his influence as well? On the papers, he was a simple civil servant who held a _relatively_ high position in his office.

While he was thinking, she shot him a guilty look which she didn't quite manage to conceal in time. But of course. Had she been planning on threatening him, on using him as leverage against Mycroft? Ha! As if the large-nosed git would even glance at the bait.

"Yeah, sorry, I scrapped that plan already," she said contritely, noticing that he had found her out.

He waved a hand to show he wasn't offended in the slightest. In fact, he rather admired her nerve. "Why not go to him directly?" he asked, curious. "You wasted time coming here to Karachi. You could have found my brother in the center of London." He paused, considering. "Or at the very least, baited him with a nice, large, chocolate eclair."

"Oh, I don't think he'd be too sympathetic with people like me," she said with little humour.

Sherlock peered at her and she stared at him straight back. "Not a criminal mastermind," he said.

She looked amused. "No."

"A spy. A disgraced soldier."

Her fingers twitched and her eyes narrowed. "Stop it. You're just building up to your dramatic revelation; I know you're not guessing."

Clever.

"You're carrying weapons, and you know how to use them well. You were prepared to use me for your own benefit – but," he barreled on as she opened her mouth in protest, "you also offered me help in return. So dubious morals – perhaps motivated by desperation or vigilantism, perhaps by malice, though I doubt the latter – but a strong sense of justice nonetheless."

She offered him neither agreement nor denial, so he continued: "You've abandoned your American accent, so no plans to return, at least for the moment – bitter feelings, there, going by your expression. Perhaps you've been done an injustice by the government and thus you shirk to deal with them directly again, which is why you came to me instead of Mycroft. But you've also been _trained_ by them. In how to hide, how to track, how to blend in. Manipulate. Kill."

At his last word, the woman hid a flinch; but when she spoke, her voice betrayed no emotion. "What's your evaluation, detective?"

"A government agent. CIA, going by your level of training and statistical probability. You were recruited for your linguistic abilities – obvious going by how quickly you solved that code – and you ended up working as an assassin as your furthered your career, though they love to pretend there's no such position. It was inevitable: keen vision, a crack shot; skilled cryptanalyst, so quick with languages. But they eventually asked you to do something you didn't agree with, so you ran; but one can never _leave_ the CIA, can they, without their say."

"No," she said frankly. She looked wan and tired but impressed by his speech. "It's not easily done."

Sherlock clasped his hands behind his back. "So now you freelance as an assassin. You have skills that certain people value, and you need the money. Understandable."

"Is it?" she asked, quirking an eyebrow. "You help people. I kill them."

"I've put people in jail who committed murder to feed their family. My military flatmate's killed those who were fighting for their beliefs just as much as he was."

She looked bothered at his nonchalance. "Those aren't fair comparisons."

He replied simply, "I'm not the police."

"But you work with them," she pointed out.

"You worked for the CIA."

"Yes, and they taught me how to play God for a paycheque," she said, frowning – not at Sherlock, but at whatever was plaguing her mind. Ah. She had expected him to judge her harshly for her occupation, and his reactions weren't matching her calculations. But how could he, when she herself so divaricated from the stereotype?

"One could argue," he said, "that the world needs people like you."

"I agree," she said curtly; and once again, Sherlock was forced to pause at her unexpected response. She continued speaking in the same tight voice. "I kill people who deserve to be killed; that's my job description. But why should I have the power to decide whether someone deserves to live or to die? Strangers I've never met?" Her blue eyes met his, flaring suddenly with a fierce energy. "Can you deduce that, Mr Holmes, when you look at someone? Can you see who deserves to be pulled out like a weed—" Her voice turned murderous, and Sherlock's eyes grew wide. "— and who," she said, at once quiet and solemn, "deserves to be spared? To go on in life without ever knowing that their name was written on a paycheque, never cashed?"

"I…" Sherlock trailed off, but she didn't seem to hear him.

"You see, the world _does_ need people like me. But I don't want to _be_ that person anymore. I don't want to be so desperate as to… to keep having to make those decisions." For a tense moment, she worked her tongue behind her teeth, clearly wanting to say something. "Everything I did – and still _do_ – was to survive," she finally stated. "Nothing more than that."

Nothing more, or so she said. But Sherlock recalled of the rushing joy in his heart and mind when he was pursuing a case. He thought of John, who lay awake at night thinking of the battlefield, who couldn't quite hide the glint of eagerness in his eyes when he tore after Sherlock in the dead of the night, despite all his griping. So he couldn't help asking her, "Not for the thrill?"

She shook her head so vehemently that the barrette she wore on the back of her head came undone and clattered to a stop at Sherlock's feet. Her hair tumbled down to just past her shoulders and left her looking much younger than mere moments ago. Mere moments ago, she had been a hardened ex-agent. Now she simply looked lost. He picked up the barrette and handed it to her wordlessly, noting the six small pearls which adorned it. She held it in her hands as if it were the most precious object she possessed. "I bet you could have solved this case," she murmured to herself.

And then she sighed, looking back up at him. "No. Maybe I… enjoyed the job once upon a time, because there _are_ bad people in the world, Mr Holmes, and I could do something about it, just like you. But not anymore."

"You're certain?" he asked, already knowing her response.

"Extremely," she said firmly.

There was one more piece of data he needed. "And what if I refuse?"

A flash of anger appeared in her eyes that would have made John reach for his gun, but it disappeared as soon as he registered it. In its place was a cool resignation. "I didn't give you a chance to refuse my offer, so that wasn't fair of me," she acknowledged. "With everything you know about me, if you weren't, you know, _you_ , then… shit. I've been living way too long like this." She pressed a hand to her forehead and said resolutely, "Look, if you refuse, then so be it. I'll find another way. Well?"

It was decided.

"Mycroft owes me anyway," Sherlock said with a sniff, and picked up his phone.

* * *

The nameless woman, the ex-agent, his one-time partner, was to stay in his motel room for a few more days until one of Mycroft's own agents arrived. She agreed reluctantly, wary with the arrangement, but told Sherlock to tell his brother that _if_ Mycroft went back on his word…

Well, let's just say Sherlock typed up that text with glee.

"Thank you," she told him sincerely, as Sherlock headed to the door. "I don't know if I'll ever see you again, so thanks."

"You know where to find me," he said, "if you plan on staying in London."

She hummed, considering the possibility. "Well, since I've already mastered the posh English accent in your mighty presence…"

"No, it's still quite terrible."

The woman gave a full blown, easy laugh and approached him, looking as if she wanted to embrace him; when he stilled, she smiled gently and held out a hand instead. "Thanks again, Mr Holmes. Not everyone gets a chance at a second life."

"Sherlock," he found himself saying unexpectedly, grasping her hand. In his mind, John shot him a look of surprise and approval. _You're getting better at this people thing._

"Sherlock," she agreed, the smile lingering on her face. "You know, I might take a year or two off from being normal just yet, after meeting with your brother. I have one more thing to see to, a personal matter. A certain businessman," she said darkly.

Before he could inquire, she brightened again immediately, though a hint of ill-boding remained. "Hell, maybe I could become a nurse, like I've always wanted. I could use a bit of mundane. I'm in my thirties, I need to settle down."

"You don't seem like the domestic type," he said.

She shrugged. "Yes, well. Neither do you, but _you_ found someone to live with."

"John's my—"

"Partner, I know. I read his blog." She looked at him fondly. "Seems you're just as human as he suspects you are."

Sherlock found himself at a loss of words, so he nodded once, turned on his heels, and headed out the door.

"Goodbye, Sherlock," she said in a soft voice. "And thank you for everything."

* * *

His phone vibrated with a text from John:

**Being 'escorted' to His Highness at the Diogenes.**

**You're not in Aberdeen, are you? – JW**

Yes, John _could_ be perceptive sometimes.

As he flew back toward England, looking out from the window at a rapidly darkening sky, Sherlock realized that he never did end up finding out her name. And, he mused, perhaps that was what she wanted.

**The End**

**Author's Note:**

> * "Don't bother me" in Urdu
> 
> Sherlock and Irene's scene is a reimagining of Steven Moffat's description of what may have happened after the rescue: sherlockology(.)com/news/2015/6/2/sherlocked-after-sherlock-rescued-irene-020615
> 
> Also, following the canon timeline, our nameless assassin would have already been living an ordinary second life as Mary in 2012. Thankfully, this is fanfiction. Established timelines are mere suggestions, no?
> 
> Many thanks to the talented VassaR for the Russian translation of this story here: https://ficbook(.)net/readfic/5146907


End file.
